CN112448363A - Electrical safety system providing overcurrent protection of electrical circuits in a vehicle - Google Patents
Electrical safety system providing overcurrent protection of electrical circuits in a vehicle Download PDFInfo
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- CN112448363A CN112448363A CN202010885209.6A CN202010885209A CN112448363A CN 112448363 A CN112448363 A CN 112448363A CN 202010885209 A CN202010885209 A CN 202010885209A CN 112448363 A CN112448363 A CN 112448363A
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- 239000004065 semiconductor Substances 0.000 description 2
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
- H02H3/08—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to excess current
- H02H3/087—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to excess current for dc applications
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H1/00—Details of emergency protective circuit arrangements
- H02H1/06—Arrangements for supplying operative power
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
- H02H3/08—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to excess current
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H9/00—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection
- H02H9/02—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection responsive to excess current
- H02H9/025—Current limitation using field effect transistors
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- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05F—SYSTEMS FOR REGULATING ELECTRIC OR MAGNETIC VARIABLES
- G05F5/00—Systems for regulating electric variables by detecting deviations in the electric input to the system and thereby controlling a device within the system to obtain a regulated output
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Abstract
An electrical safety system is provided that provides overcurrent protection for an electrical circuit in a vehicle. The system comprises: the safety protection circuit comprises a main safety device comprising an N-type transistor and an auxiliary safety device comprising a P-type transistor, wherein the main safety device and the auxiliary safety device are enabled alternately under the command of a controller. The N-type transistor and the P-type transistor have overcurrent protection functions in a first working mode and a second working mode respectively. The auxiliary safety device further comprises: a passive component connected in series with the P-type transistor for providing a voltage drop when current passes through the passive component; and a drive circuit for controlling the turn-off of the P-type transistor under control of a voltage drop exceeding a first threshold in the second operation mode.
Description
Technical Field
The present disclosure relates to the field of electrical safety systems or devices that provide overcurrent protection of an electrical circuit. Such a system may be used, for example, in a vehicle to protect the devices of the vehicle's electrical circuits in the event of a failure.
Background
Conventionally, vehicles use electrical fuses that include a metal wire or strip that melts when an excessive current flows, thereby interrupting the current. The advantage of fuses is that they are passive components that do not consume power. The quiescent current through the fuse is zero. Thus, the fuse does not consume power when the electrical circuit of the vehicle is in the park mode. Another advantage is the ability of the fuse to remove high power from a faulty system. In other words, the fuse can drain a high current and its quiescent current is equal to zero regardless of its discharge capability. However, the fuse has a major disadvantage because it is a sacrificial device. Fuses must be replaced once they are functional, which is inconvenient in an automotive environment.
It is known to use electronic switching devices (commonly referred to as "high-side switches" or "high-side drivers") as a substitute for fuses. The high-side switch includes a transistor (such as a MOSFET transistor) that provides overcurrent protection and electronics that control the transistor. In order to be able to switch high currents (typically between 100 milliamps and several hundred amps), high-side switches are equipped with N-type MOSFET transistors. They can safely drive high currents into complex grounded loads that conform to the automotive environment. However, high-side switches have a high quiescent current, typically a few milliamps, compared to zero milliamps (for a conventional fuse).
Vehicles typically spend a significant amount of time in a park mode where current is drained from the battery. In order not to drain too much energy from the battery, the quiescent current of the various components of the circuitry within the vehicle must be very low. A quiescent current of a few milliamps is too high for this very low power consumption constraint of the vehicle in the parking mode.
There is a need for improvements in the context of electrical safety systems that provide overcurrent protection of, for example, electrical circuits in a vehicle, that can be reused after being functional, and that also have very low quiescent currents (e.g., to meet electrical requirements in an automotive environment).
Disclosure of Invention
A first aspect of the present disclosure relates to an electrical safety system providing overcurrent protection of an electrical circuit, the electrical safety system comprising a primary safety device including a first transistor providing overcurrent protection, characterized in that:
the electrical safety system further comprises an auxiliary safety device comprising a second P-type transistor providing overcurrent protection of the circuit, the main safety device and the auxiliary safety device alternately providing overcurrent protection in a first operating mode and a second operating mode of the circuit, respectively; and
the secondary security device further comprises: a passive component connected in series with the second P-type transistor, the passive component providing a voltage drop when current passes through the passive component; and a drive circuit that controls turning off of the second P-type transistor under control of a voltage drop exceeding a first threshold.
Typically, the first mode of operation consumes more power than the second mode of operation. Such an electrical safety system may be integrated in a vehicle to protect the electrical circuitry in the vehicle.
The electrical safety system includes a primary safety device including a first transistor, such as an N-type transistor, and a secondary safety device including a P-type transistor. The two transistors are alternately turned on in a first operating mode and a second operating mode of the circuit, respectively, to alternately implement an overcurrent protection function. The auxiliary safety device comprises: a passive component connected in series with the P-type transistor to provide a voltage drop when current passes through the passive component; and a drive circuit that controls turning off of the P-type transistor under control of a voltage drop exceeding a first threshold in the second operation mode.
In a first mode of operation (e.g., when the vehicle is operating), such a system allows the use of a master safety device that uses a power transistor (e.g., an N-type transistor) and is capable of removing high current from the fault circuit. In the second operating mode (e.g., when the vehicle is parked), the master safety device is turned off (deactivated) and does not draw any current. In order to implement the overcurrent protection function in the second operating mode, a secondary safety device equipped with a P-type transistor is used. The overcurrent protection function is implemented by a P-type transistor coupled to a passive component that provides a voltage drop that is used as a command to control the turn-off of the P-type transistor when current passes through the passive component.
The present configuration has the advantage of extremely low (equal or very close to zero) electrical consumption due to the use of passive components and P-type transistors providing a voltage drop in the second mode of operation. In case of excessive current flowing through the passive components, the passive components provide a high voltage drop which controls the turn-off of the P-type transistor and thus the current is interrupted. Therefore, the overcurrent protection function is realized based on the structural elements (the P-type transistor and the voltage drop passive component) that do not consume electric power. Thus, the quiescent current of such a system is zero or very close to zero.
In the first operating mode, the main safety device is used and allows high currents to be drawn in the event of a fault.
A controller (such as a controller of a vehicle incorporating an electrical safety system) may control the turning on of the first transistor of the primary safety device and the turning off of the second transistor of the secondary safety device in a first mode of operation of the circuit, and control the turning off of the first transistor of the primary safety device and the turning on of the second transistor of the secondary safety device in a second mode of operation of the circuit.
A second aspect of the present invention relates to an electrical safety device for providing overcurrent protection of an electrical circuit, characterized in that the electrical safety device comprises:
a P-type transistor providing overcurrent protection of the circuit;
a passive component connected in series with the P-type transistor to provide a voltage drop when current passes through the passive component, an
A drive circuit that controls the turning off of the P-type transistor under control of a voltage drop exceeding a first threshold.
Advantageously, the passive component providing the voltage drop comprises a resistive element.
Advantageously, the drive circuit comprises a first switch controlled by the voltage drop:
as long as the voltage drop does not exceed the first threshold, the first switch is turned off, and
the first switch is turned on under control of a voltage drop exceeding a first threshold value to output a control signal that controls turning off of the P-type transistor.
Advantageously, the first switch is a bipolar transistor or a MOSFET transistor. These types of transistors have zero quiescent current.
Advantageously, the drive circuit further comprises a second switch through which the overcurrent protected P-type transistor is connected to ground.
The second switch may be an N-type transistor.
Advantageously, the drive circuit further comprises a latch means for controlling said second switch with an output signal dependent on a control signal received via the reset input or the set input, and the first switch outputs the control signal to the latch means.
Advantageously, the drive circuit further comprises a third switch controlled by the voltage drop:
turning off the third switch as long as the voltage drop does not exceed a second threshold, the second threshold being less than the first threshold; and is
The third switch is turned on and then a wake-up signal is sent, under control of a voltage drop exceeding a second threshold.
Advantageously, the third switch is a bipolar transistor or a MOSFET.
In a particular embodiment, the first switch is a MOSFET and the third switch is a bipolar transistor. The threshold voltage of a MOSFET is typically higher than the threshold voltage of a bipolar transistor. This configuration allows the physical characteristics of the two different types of transistors (MOSFET and bipolar) to be used to define a first "high" threshold and a second "low" threshold.
A third aspect of the present disclosure relates to a vehicle incorporating an electrical safety system or electrical safety device as hereinbefore defined.
Drawings
Other features, objects, and advantages of the disclosure will become more apparent from the detailed description of the non-limiting embodiments, which proceeds with reference to the accompanying figures.
Fig. 1 shows an electrical safety system providing overcurrent protection of an electrical circuit according to a first embodiment;
fig. 2 shows the auxiliary electrical safety device of the system of fig. 1.
Detailed Description
Fig. 1 shows an electrical safety system 100 providing overcurrent protection of an electrical circuit (not shown) according to a first embodiment. For example, the system 100 may be integrated in a vehicle with the electrical and electronic components of the vehicle being supplied with current from a car battery of, for example, 12V. The electrical safety system 100 discharges an overcurrent caused by a fault in an electrical circuit, such as an overload or a short circuit. More specifically, the main function of the electrical safety system 100 is to interrupt the current in the circuit when the current reaches the overcurrent detection value.
The electrical safety system 100 has a primary safety device 1 and a secondary safety device 2. Both safety devices 1 and 2 are connected (in parallel) to an input terminal 3a and an output terminal 3b of the circuit. The primary safety device 1 provides overcurrent protection of the circuit in a first mode of operation of the circuit, while the secondary safety device 2 provides overcurrent protection of the circuit in a second mode of operation of the circuit. Thus, the primary and secondary safety devices 1, 2 alternately provide overcurrent protection of the circuit in a first and second mode of operation of the circuit, respectively.
The first mode of operation is expected to consume more electrical energy than the second mode of operation. Typically, the first mode of operation corresponds to a vehicle operating mode, such as a drive mode, and the second mode of operation corresponds to a vehicle non-operating mode (e.g., the vehicle is stopped and parked, and the circuit is in a sleep mode). In the second mode of operation, the circuit operates in a sleep mode with very low power consumption. The primary safety device 1 is intended to be used in a first mode of operation to provide an overcurrent protection function and to be deactivated in a second mode of operation. On the other hand, the secondary safety device 2 is intended to be used in the second operating mode to provide an overcurrent protection function and to be deactivated in the first operating mode. In other words, the main safety device 1 and the auxiliary safety device 2 alternately operate to provide an overcurrent protection function of the circuit.
In the present embodiment, the master safety device 1 comprises a first transistor 10, for example an N-type transistor, to provide an overcurrent protection function, the first transistor 10 being connected between the input terminal 3a and the output terminal 3b of the circuit. The master security device 1 further comprises a charge pump 11 to drive the transistor 10 in dependence of a control signal "ON" (enabled) or "OFF" (disabled) from the controller 4 external to the master security device 1. The charge pump 11 is connected to the command gate of the first transistor 10 and to a connection point 12 between the input terminal 3a and the output terminal 3b (e.g., between the input terminal 3a and the transistor 10 shown in fig. 1). The control signal "ON" is used to turn ON (or enable, or turn ON) the first transistor 10 so that current can flow through the transistor 10, and the control signal "OFF" is used to turn OFF (or disable, or turn OFF) the first transistor 10 so that current flowing through the transistor 10 is interrupted. The main safety device 1 is for example a high-side switch known on the market. It has a good ability to safely drive high currents into a grounded load in the event of a fault or overload in the electrical circuit of the vehicle.
The sub safety device 2 is an electronic device that provides an overcurrent protection function with extremely low power consumption close to zero by utilizing physical characteristics of some electrical components, which will become apparent from the description later. It has a displacement capacity to remove current in case of a fault, which may be lower than the displacement capacity of the primary safety device 1.
A first embodiment of the secondary security device 2 will now be described with reference to figure 2.
Referring to fig. 2, the secondary security device 2 includes: a second P-type transistor 20 for providing an overcurrent protection function of the vehicle circuit; and a passive component 21 connected in series with the P-type transistor 20 for providing a voltage drop when a current flows through said passive component 21. The overcurrent protected transistor 20 is, for example, a PMOSFET.
A drive circuit 22 is also provided to exceed the first threshold V in a second mode of operation of the circuitTH1Is controlled by the voltage drop (provided by component 21) of the second P-type transistor of the overcurrent protection 20.
In the first placeIn one embodiment, in the second mode of operation of the circuit, the driving circuit 22 is exceeding the second threshold VTH2Under control of the voltage drop (provided by component 21) generates a wake-up (or enable) control signal.
First threshold value VTH1And a second threshold value VTH2Is the voltage value. Second threshold value VTH2Less than a first threshold value VTH1。
The basic function of the driver circuit 22 is to control the switching off of the second transistor 20 for overcurrent protection in the second operating mode. The wake-up function of the driver circuit 22 is optional.
The drive circuit 22 has a first switch 220 controlled by a voltage drop 21, and:
as long as the voltage drop provided by the component 21 does not exceed the first threshold value VTH1The drive circuit 22 is turned off; and is
Above a first threshold value VTH1Under the control of the voltage drop 21, the driving circuit 22 is turned on to output a control signal for controlling the P-type transistor 20 to be turned off.
In the first embodiment, the first switch 220 is a transistor. For example, the transistor 220 is a bipolar transistor or a MOSFET (metal oxide semiconductor field effect transistor). The transistor 220 is connected to both terminals of the voltage drop part 21 so that the voltage drop controls the operation of the transistor 220. If the transistor 220 is a bipolar transistor, the base and the emitter of the transistor 220 are connected to the two terminals of the voltage drop part 21, respectively. If the transistor 220 is a MOSFET, the gate and the source of the transistor 220 are connected to both terminals of the voltage drop part 21, respectively, so that the voltage drop corresponds to VGS(i.e., the voltage between the gate and source of transistor 220) and controls the operation of transistor 220.
The transistor 220 (first switch) operates as follows:
as long as the voltage drop is less than the first threshold value VTH1Transistor 220 is blocked and operates as an open switch; and is
If the voltage drop exceeds a first threshold value VTH1Then transistor 220 saturates and operates as a closed switch.
First threshold value VTH1Corresponding to the threshold voltage of transistor 220.
For example, the threshold voltage VTH1Between 1V and 5V, e.g. threshold voltage VTH1Equal to 1.2V.
The passive component 21 (also referred to as "voltage drop component") has a resistive element. For example, the passive component 21 has only a resistance. The resistance value of the passive component 21 is adapted to provide a value equal to the threshold voltage VTH1Is adapted to reach or exceed the overcurrent detection value I when the current passing through the section 21 reaches or exceeds the overcurrent detection value ITH1The conduction of the first switch 220 is controlled. The overcurrent detection value corresponds to a current threshold value beyond which it is desirable to implement an overcurrent protection function and interrupt the flow of current in the circuit. In other words, when the current flowing through the component 21 reaches the current threshold ITH1(or overcurrent detection value), the resistance value R of the voltage drop section 21 is determined to provide a value equal to VTH1The voltage drop of (c). More specifically, in the present embodiment, the resistance value R of the voltage drop part 21 is equal to VTH1/ITH1. For example (only exemplary values are given to illustrate the present disclosure):
if VTH11.2V and ITH1＝200mA；
Then R ═ VTH1/ITH1＝1.2/0.2＝6Ω。
In the drive circuit 22, the switch 220 controls the turning off (or cutoff) of the overcurrent-protected P-type transistor 20 by the second switch 221. The second switch 222 is, for example, an N-type transistor that controls a P-type transistor of the overcurrent protection 20. It has the function of grounding the command gate of the P-type transistor 20. In other words, the command gate of the P-type transistor 20 is connected to ground through the N-type transistor 222.
The second switch 221 is controlled by an electronic latch component 223. Latch component 223 includes a set input "S", a reset input "R", and an output having two stable states set according to a control signal received through either the set input or the reset input. Advantageously, the latch component 223 comprises only MOSFETs and/or bipolar transistors to implement the latch function while avoiding any quiescent current. The output of latch section 223 is connected to the command gate of switch 221. The latch section 223 outputs a control signal that controls the second switch 221. The set and reset inputs of latch component 223 are here connected to external controller 4 via two respective links. The set input terminal receives a control signal "ON" (enabled) from the external controller 4 to turn ON (or turn ON) the second switch 221 and thus the P-type transistor 20. The reset input terminal receives a control signal OFF from the external controller 4 to turn OFF (or cut OFF) the second switch 221 and thus the P-type transistor 20.
The first switch 220 is also connected to the reset input of the latch part 223 and sends a control signal OFF (disable) to the reset input of the latch part 223 to turn OFF the second switch 221 when enabled (or turned on) to turn OFF the P-type transistor 20, as will be explained later.
In the first embodiment, the drive circuit 22 further has a third switch 224 to generate a wake-up or enable signal when, in the second mode of operation, the current flowing through the voltage drop means 21 increases slightly due to normal action of one or more devices of the vehicle. The function of the switch 224 is, in the second operating mode, when the current through the voltage drop means 21 exceeds a second threshold value VTH2Then a wake-up signal is sent to the circuit, said second threshold value VTH2Less than a first threshold value VTH1. The wake-up signal may re-enable the main security device 1 directly or through the controller 4, since it is expected that the circuit will soon enter the first mode of operation. Like the first switch 220, the third switch 224 is controlled by the voltage drop and is:
as long as the voltage drop (provided by the component 21) does not exceed the second threshold VTH2Then the third switch 224 is turned off; and is
Above a second threshold value VTH2Turns on the third switch 224 under control of the voltage drop and then sends a wake-up signal to the circuit.
In the first embodiment, the third switch 224 is a transistor. For example, transistor 224 is a bipolar transistor or MOSFET (gold)An oxide semiconductor field effect transistor). The transistor 224 is connected to both terminals of the voltage drop section 21 so that the voltage drop controls the operation of the transistor 224. If the transistor 224 is a bipolar transistor, the base and the emitter of the transistor 224 are connected to the two terminals of the voltage drop section 21, respectively. If the transistor 224 is a MOSFET, the gate and the source of the transistor 224 are connected to both terminals of the voltage drop section 21, respectively, so that the voltage drop corresponds to VGS(i.e., the voltage between the gate and source of transistor 224) and controls the operation of transistor 224. Transistor 224 operates as follows:
as long as the voltage drop is less than the second threshold value VTH2Transistor 224 is blocked and operates as an open switch; and is
If the voltage drop exceeds a second threshold value VTH2Then transistor 224 saturates and operates as a closed switch.
Second threshold value VTH2Corresponding to the threshold voltage of transistor 224. Advantageously, the threshold voltage VTH2Between 0.6V and 1V. For example, the threshold voltage VTH2Equal to 0.7V. In the illustrative example given previously, the resistance value R of the voltage drop section 21 is equal to 6 Ω. In that case, if the current through the component 21 exceeds VTH2when/R is 0.7/6 ≈ 116mA, the switch 224 is turned on.
Due to the second threshold value VTH2Less than a first threshold value VTH1So that the voltage drop can be below VTH1In the case of or at VTH1Before exceeds VTH2. In this case, the third switch 224 allows waking up one or more devices of the circuit in the vehicle, in particular the master safety device 1. When the main safety device 1 is reactivated, the calculator 4 (controller) of the vehicle controls the turning OFF of the P-type transistor 20 of the overcurrent protection of the auxiliary safety device 2 by sending a control signal OFF to the reset or "R" input of the latch section 223.
A controller 4 is provided to control the operation of the primary and secondary security devices 1, 2. More specifically, the controller 4 controls:
in a first mode of operation of the circuit, the overcurrent-protected N-type transistor 10 of the primary safety device 1 is turned on and the overcurrent-protected P-type transistor 20 of the secondary safety device 2 is turned off;
in a second mode of operation of the circuit, the overcurrent-protected N-type transistor 10 of the primary safety device 1 is turned off and the overcurrent-protected P-type transistor 20 of the secondary safety device 2 is turned on;
the first operating mode consumes more power than the second operating mode.
The controller 4 is, for example, a calculator of the vehicle.
The operation of the security system 100 will now be described.
For example, when the vehicle is operating in the drive mode, its circuitry is in a first operating mode. In this first mode of operation, the main safety device 1 operates in a conventional manner to provide an overcurrent protection function for the circuit. The overcurrent-protected N-type transistor 10 is turned on at the command of the controller 4 and operates as a closed switch so that current can flow through the transistor 10 and the input terminal 3a and the output terminal 3b of the vehicle circuit. The input terminal 3a and the output terminal 3b are connected to each other through an N-type transistor 10 (closed switch).
In this first mode of operation, the secondary security device 1 is deactivated. This means that the overcurrent protected P-type transistor 20 is turned off and operates as an open switch. Therefore, no current flows through the voltage drop section 21. The voltage drop is zero and therefore the first switch 220 and the third switch 224 are also turned off and operate as open switches. Deactivation of the auxiliary safety device 1 is typically triggered by a pulse signal "OFF" sent from the controller 4 to the set input of the latch section 223. As a result, the output signal from the latch section 223 controls the second switch 221 to be turned off and to operate as an open switch. In this state, the transistor 20 is not grounded and is therefore turned off.
Then, we assume that the vehicle is stopped and parked. Thus, the circuitry of the vehicle enters a second mode of operation (or "park mode" or "sleep mode"). In the second operating mode, the electronic devices of the vehicle enter a sleep mode and the power consumption of these electronic devices is zero or close to zero. To enter the second mode of operation, the controller 4 sends a control signal OFF to the secondary safety device 2 which deactivates the primary safety device 1, while sending a control signal ON which activates the secondary safety device 2.
When the main safety device 1 receives the control signal OFF from the controller 4, the charge pump 21 is stopped, and thus the overcurrent-protected N-type transistor 10 is turned OFF and operates as an open switch.
In the auxiliary safety device 20, the control signal ON from the controller 4 is received by the set input terminal of the latch section 223. Accordingly, the output signal from the latch part 223 is changed and thus the second switch 221 is controlled to be turned on. Therefore, the second switch 221 operates as a closed switch under the control of the output signal from the latch section 223. As a result, the command gate of the P-type transistor 20 is connected to ground through the second switch 221, which causes the P-type transistor 20, which operates as a closed switch, to be turned on. Therefore, the input terminal 3a and the output terminal 3b of the circuit are connected to each other through the voltage drop section 21 and the P-type transistor 20.
In the second mode of operation, the current through the voltage drop means 21 is typically equal to or close to zero, since most of the electronics of the circuit are in a sleep or standby mode. As a result, the voltage drop provided by the component 21 is equal to or close to zero. Thus, the first switch and the third switch are turned off and operate as open switches.
In the second operating mode, according to the first case, the current flowing through the voltage drop means 21 is slightly increased due to the normal action performed by one or more electronic devices of the vehicle. This small increase in current results in a small increase in the voltage drop provided by the component 21. This situation may occur, for example, when a user with a contactless key approaches the vehicle. The contactless key wakes up some devices within the vehicle, which causes the current in the circuit to increase. If the voltage drop produced exceeds a second threshold voltage VTH2It has the effect of turning on the third switch 224. Third switch 224 is over VTH2Is turned on and thus sends a wake-up signal to the circuit. For example, a wake-up signal from third switch 225 is used to enable or wake-up controller 4, and then controller 4 may be enabled by switching toThe charge pump 21 sends a signal ON to enable the primary security device 1 and disables the secondary security device 2 by sending a signal OFF to the latch section 223. As previously indicated, the wake-up function provided by the third switch 224 is optional.
As long as the voltage drop remains at the first threshold VTH1Thereafter, the first switch 220 remains off and continues to operate as an open switch.
In the second operating mode, according to the second situation, the current flowing through the voltage drop component 21 increases too much, which results in a significant increase in the voltage drop, for example due to a fault in the circuit (overload, short circuit, etc.). In this case, the voltage drop generally exceeds the first threshold voltage V not only for a very short period of timeTH1And also exceeds a second threshold voltage VTH2. The first switch 220 is exceeding the first threshold VTH1Is turned on under the control of the voltage drop. As a result, the first switch 220 outputs a control signal that is sent to the reset input of the latch section 223, which in turn controls the second switch 221 to turn off under the control of the output signal (change of state thereof) from the latch section 223. When the second switch 221 is turned off, the overcurrent-protected P-type transistor 20 is no longer grounded and is therefore turned off. When the transistor 20 is turned off, the current flowing through the transistor 20 is interrupted. Thus, overcurrent protection is achieved.
At the above-mentioned voltage drop exceeding the first threshold value VTH1Also the voltage drop exceeds the second threshold value VTH2And, as a result, the third switch 224 is turned on and sends a wake-up signal to the circuit.
In a particular embodiment, the first switch 220 is a MOSFET and the third switch 224 is a bipolar transistor. This configuration is advantageous because the threshold voltage of a bipolar transistor is typically less than the threshold voltage of a MOSFET transistor. Thus, by simply using the physical characteristics of these two different types of transistors, it is allowed to provide a "high" voltage threshold V for the overcurrent protection functionTH1And a "low" voltage threshold VTH2。
In the first embodiment, the resistance value of the voltage drop section 21 is determined according to a fixed overcurrent detection value (e.g., 200mA) and the threshold voltage (e.g., 1.2V) of the transistor 220 of the first switch.
In a variant, the threshold voltage VTH2Rather than being equal to the threshold voltage of transistor 224, it depends on the threshold voltage of transistor 224 coupled to the resistive element.
In another variant, the threshold voltage VTH1Instead of being equal to the threshold voltage of transistor 220, it depends on the threshold voltage of transistor 220 coupled to the resistive element.
This configuration allows the threshold voltage value V to be adjustedTH1And/or VTH2。
The second embodiment of the electrical safety system is similar to the first embodiment and differs only in that the secondary safety device does not include the third switch 224.
Claims (15)
1. An electrical safety system (100) providing overcurrent protection of an electrical circuit, the electrical safety system (100) comprising a primary safety device (1), the primary safety device (1) comprising a first transistor (10) providing overcurrent protection of the electrical circuit, characterized by:
the electrical safety system (100) further comprises an auxiliary safety device (2), the auxiliary safety device (2) comprising a second P-type transistor (20) providing overcurrent protection of the electrical circuit, the main safety device (1) and the auxiliary safety device (2) being alternately used in a first operating mode and a second operating mode of the electrical circuit, respectively, to provide the overcurrent protection, and
the secondary security device (2) further comprises: a passive component (21), the passive component (21) being connected in series with the second P-type transistor (20) to provide a voltage drop when a current passes through the passive component (21); and a drive circuit (22), the drive circuit (22) exceeding a first threshold value (V)TH1) Controls the turn-off of the second P-type transistor (20) under control of the voltage drop.
2. The electrical safety system (100) of claim 1, wherein the passive component (21) providing the voltage drop comprises a resistive element.
3. The electrical safety system (100) of claim 1 or 2, wherein the drive circuit (22) comprises a first switch (220) controlled by the voltage drop:
as long as the voltage drop does not exceed the first threshold value (V)TH1) The first switch (220) is turned off, and
upon exceeding the first threshold value (V)TH1) Under the control of the voltage drop, the first switch (220) is turned on to output a control signal for controlling the turning off of the P-type transistor (20).
4. The electrical safety system (100) of claim 3, wherein the first switch (220) is a bipolar transistor or a MOSFET transistor.
5. The electrical safety system (100) according to any one of the preceding claims, wherein the drive circuit (22) further comprises a second switch (221), the P-type transistor (20) of the secondary safety device (2) being connected to ground through the second switch (221).
6. The electrical safety system (100) of claim 5, wherein the second switch (221) is an N-type transistor.
7. The electrical safety system (100) of claim 5 or 6, wherein the drive circuit (22) further comprises: a latch section (223) controlling the second switch (221) with an output signal that depends on a control signal received through a reset input or a set input of the latch section (223), and the first switch (220) outputs a control signal to the latch section (223).
8. The electrical safety system (100) of any one of claims 3 to 7, wherein the drive circuit (22) further comprises a third switch (224) controlled by the voltage drop:
as long as the voltage drop does not exceed the second threshold value (V)TH2) Turning off the third switch (224), the second threshold being less than the first threshold, an
Upon exceeding the second threshold value (V)TH2) The third switch (224) is turned on and then a wake-up signal is sent.
9. The electrical safety system (100) of claim 8, wherein the third switch (224) is a bipolar transistor or a MOSFET transistor.
10. The electrical safety system (100) of claims 3 and 8, wherein the first switch (220) is a MOSFET transistor and the third switch (224) is a bipolar transistor.
11. The electrical safety system (100) according to any one of the preceding claims, wherein the first transistor of the primary electronic safety device is an N-type transistor.
12. An electrical safety device (2) providing overcurrent protection of an electrical circuit, the electrical safety device (2) comprising:
a P-type transistor (20), the P-type transistor (20) providing overcurrent protection for the circuit;
a passive component (21), the passive component (21) connected in series with the P-type transistor (20) to provide a voltage drop when current passes through the passive component;
a drive circuit (22), the drive circuit (22) exceeding a first threshold value (V)TH1) Controls the turn-off of the P-type transistor (20) under control of the voltage drop.
13. The electrical safety device (2) according to claim 12, characterized in that the passive component (21) providing the voltage drop comprises a resistive element.
14. The electrical safety device (2) according to claim 12 or 13, characterized in that the drive circuit (22) comprises a first switch (220) controlled by the voltage drop:
as long as the voltage drop does not exceed the first threshold value (V)TH1) The first switch (220) is turned off, and
upon exceeding the first threshold value (V)TH1) To turn on the first switch (220) to output a control signal that controls the turn-off of the P-type transistor (20).
15. A vehicle incorporating an electrical safety system according to any one of claims 1 to 11 or an electrical safety device according to any one of claims 12 to 14.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| EP19194381.0 | 2019-08-29 | ||
| EP19194381.0A EP3787139A1 (en) | 2019-08-29 | 2019-08-29 | Electrical safety system for providing overcurrent protection of an electrical circuit in a vehicle |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN112448363A true CN112448363A (en) | 2021-03-05 |
| CN112448363B CN112448363B (en) | 2023-05-02 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202010885209.6A Active CN112448363B (en) | 2019-08-29 | 2020-08-28 | Electrical safety system providing over-current protection of electrical circuits in a vehicle |
Country Status (3)
| Country | Link |
|---|---|
| US (2) | US11362506B2 (en) |
| EP (1) | EP3787139A1 (en) |
| CN (1) | CN112448363B (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US11646566B2 (en) * | 2020-12-16 | 2023-05-09 | Lear Corporation | Apparatus for permanent supply with a switch |
| US12088183B2 (en) | 2021-10-19 | 2024-09-10 | Lear Corporation | Electrical system |
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| US6710698B1 (en) * | 1999-09-02 | 2004-03-23 | Robert Bosch Gmbh | Semiconductor fuse for electrical consumers |
| CN101820162A (en) * | 2010-05-18 | 2010-09-01 | 北京星网锐捷网络技术有限公司 | Overcurrent protector |
| CN107706882A (en) * | 2016-08-09 | 2018-02-16 | 利萨·德雷克塞迈尔有限责任公司 | Electronic fuse for the electric loading in the vehicle electronic circuit system of motor vehicle |
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| EP1724899B1 (en) * | 2005-05-17 | 2016-08-03 | Continental Automotive GmbH | Apparatus for short circuit protection |
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| US8553373B2 (en) * | 2011-08-25 | 2013-10-08 | Hamilton Sundstrand Corporation | Solid state power controller for high voltage direct current systems |
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| US10498131B2 (en) * | 2016-12-30 | 2019-12-03 | Infineon Technologies Ag | Electronic switch and protection circuit |
-
2019
- 2019-08-29 EP EP19194381.0A patent/EP3787139A1/en active Pending
-
2020
- 2020-08-19 US US16/997,039 patent/US11362506B2/en active Active
- 2020-08-28 CN CN202010885209.6A patent/CN112448363B/en active Active
-
2022
- 2022-06-07 US US17/834,357 patent/US11799282B2/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6710698B1 (en) * | 1999-09-02 | 2004-03-23 | Robert Bosch Gmbh | Semiconductor fuse for electrical consumers |
| CN101820162A (en) * | 2010-05-18 | 2010-09-01 | 北京星网锐捷网络技术有限公司 | Overcurrent protector |
| CN107706882A (en) * | 2016-08-09 | 2018-02-16 | 利萨·德雷克塞迈尔有限责任公司 | Electronic fuse for the electric loading in the vehicle electronic circuit system of motor vehicle |
Also Published As
| Publication number | Publication date |
|---|---|
| US20220376487A1 (en) | 2022-11-24 |
| US11362506B2 (en) | 2022-06-14 |
| EP3787139A1 (en) | 2021-03-03 |
| US20210066905A1 (en) | 2021-03-04 |
| CN112448363B (en) | 2023-05-02 |
| US11799282B2 (en) | 2023-10-24 |
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